JOURNAL OF APPLIED SCIENCES RESEARCH

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1 Copyright 2015, American-Eurasian Network for Scientific Information publisher JOURNAL OF APPLIED SCIENCES RESEARCH ISSN: X EISSN: X JOURNAL home page: December; 11(23): pages Published Online 31 December Research Article Effect of Single And Three Hole Fuel Injector Nozzle on Performance And Emission Characteristic of Diesel on A Vcr Engine 1 M.Mahendran, 2 R.Tamilselvan, 3 R.Prakash 1 (Assistant Professor), Department Of Mechanical Engineering, Sri Ramakrishna Engineering College, Coimbatore. 2 (Pg Scholar), M.E-Thermal Engineering, Sri Ramakrishna Engineering College, Coimbatore. 3 (Pg Scholar), M.E-Thermal Engineering, Sri Ramakrishna Engineering College, Coimbatore. Received: 23 October 2015; Accepted: 23 December AENSI PUBLISHER All rights reserved ABSTRACT Fuel injection parameters play an important role in diesel engine performance for obtaining proper combustion. The performance and emission characteristics of diesel engine depend on many parameters. An experimental study was conducted on a light duty DI diesel engine at single and three hole fuel injection to study its effect on performance and emission by using conventional diesel fuel on the single cylinder four stroke engine with the engine working at different engine loads at compression ratio Future emission regulation will require substantial reductions of NOx and CO2 emissions from diesel engines. At full load, CO and HC emissions were found same at single hole and three hole nozzle injector. The combustion in a diesel engine is governed mainly by spray formation and mixing. Important parameters governing these are droplet size, distribution concentration and injection velocity. Smaller orifices are believed to give smaller droplet size, with increase injection nozzle hole, which leads to better fuel atomization, faster evaporation and better mixing. The performance and emission characteristics were presented clearly to determine that they were found better with three hole nozzle for the light duty engine. Key words: Diesel engines, performance, fuel injection parameters, SFC, NOx,CO,HC, CO2 emission. INTRODUCTION Pollutant emission reduction is currently considered to be one of the most important targets of our society. Regulation about pollution coming from vehicles is getting more and more restrictive, so that research is focused to understand physical processes involved in the engine behaviour. One of the most important subjects in these studies on Diesel engines is the behaviour of fuel once it is injected in the combustion chamber, and its interaction with air. In these terms, it is well known that nozzle geometry and cavitation strongly affect to evaporation and atomization processes of fuel. The study of these phenomena has been the aim of previous studies in the literature. In a direct injection engine, fuel is injected into the combustion chamber as opposed to injection before the intake valve (petrol engine) or a separate pre-combustion chamber (diesel engine) Prof.Hiregouda et al has made an experimental investigation on the effect injector nozzles and models created such as fins for fuel spray on performance of a diesel engine. It is observed that 4 holes 10 fins nozzle design is given good result when compared to other designs in better performance, Better BSFC and Brake Thermal Efficiency and even fine spray can be obtained. It may be suggested that by increasing the number of fins we may achieve better results than 10 fins, as the breakdown of fuel to fine droplets is more with increased fins and easy escape due to reduced width of fin to fin gap. Rohit Sharma, et al experimental study was performed on a light duty direct injection diesel engine at 200 bar, 220 bar and 240 bar injection pressure to study its effect on performance and Corresponding Author: M.Mahendran, (Assistant Professor), Department Of Mechanical Engineering, Sri Ramakrishna Engineering College, Coimbatore. revamahe06@gmail.com

2 94 M.Mahendran et al, 2015 /Journal Of Applied Sciences Research 11(23), December, Pages:93-99 emission with changing the number of nozzle holes. It is observed that the Brake thermal efficiency for 5 hole nozzle at full load was found increasing in the order of bar injection pressure and brake specific fuel consumption found decreasing in the order of bar injection pressure. Though at 220 bar higher brake thermal efficiency and lower brake specific fuel consumption were obtained the percentage of improvement was maximum of 3%. So, increasing injection pressure and number of holes gave considerable effect on engine performance. Subhash Lahane, et al The study is aimed at reduction in NOx emission of the engine at source level and chance of wall impingement using the modified nozzle configuration (5 and 6 holes). It is observed that NOx emissions decreased with the modified nozzle configuration (increase in number of nozzle holes from 5 to 6). It decreased from 7.39 g/kw-hr with base nozzle configuration to 6.54 g/kw-hr with B20. It is observed from the experimental study that the reason for decrease in NOx emission of the biodiesel fueled diesel engine with the modified nozzle configuration (6 holes) is due to automatic retarding of dynamic injection timing and lesser localized in-cylinder temperature. A salient point emerged from the spray simulation study is that spray penetration distance is well correlated with NOx emission. 2. Experimental Test Rig: An experimental test rig is developed to undertake the thermal performance evaluation and emission characteristics evaluation of a variable compression ratio compression ignition engine fuelled with Diesel oil. The experimental test rig is suitably developed to conduct various test runs under different working conditions to evaluate the thermal performance and emission constituents of a diesel run engine in comparison with that single hole and three hole fuel injector nozzle of an engine. The experimental test rig consists of a variable compression ratio compression ignition engine, eddy current dynamometer as loading system, fuel supply system for Diesel oil supply, water cooling system, lubrication system and various sensors and instruments integrated with computerized data acquisition system for online measurement of load, air and fuel flow rate, instantaneous cylinder pressure, injection pressure, position of crank angle, exhaust emissions. Table 2.1 gives the technical specifications of different components used in the test rig. The setup enables the evaluation of thermal performance and emission constituents of the VCR engine. The thermal performance parameters include brake power, brake mean effective pressure, brake thermal efficiency, volumetric efficiency, and specific fuel consumption. Commercially available labview based Engine. Performance Analysis software package-en evaluation. The exhaust emissions of the engine are analysed using an exhaust gas analyser. The constituents of the exhaust gas measured are CO (% and ppm), CO2 (%), O2 (%), HC (ppm), NOx (ppm) and SOx (ppm). Table 2.1: Technical Specifications of Experimental Test Rig single cylinder, Four stroke, Type Water cooled, Diesel Number of cylinder One Rated power 3.5 kw at 1500 rpm Bore and Stroke 87.5 mm and 110 mm Combustion principle Compression ignition Cubic capacity litres 17.5 :1 (modified to work at 12, Compression ratio 13, 14, 15, 16, Software EnginesoftLV Engine Engine cooling LPH; Rotameter Calorimeter LPH Exhaust gas analyzer AVL 444, Five gas analyzer 3. Commercial Software EnginesoftLV: Labview based Engine Performance Anal is used for the on line performance evaluation. Fig3.1 gives an image of a typical menu during interface with Enginesoft LV. EngineSoftLV can serve most of the engine testing application needs including monitoring, reporting, data entry, data logging. The software evaluates power, efficiencies, fuel consumption and heat release. It is configurable as per engine set up. Various graphs are obtained at different operating conditions. While on line testing of the engine is in RUN mode necessary signals are scanned, stored and presented in the form of graphs. Stored data file is accessed to view the data graphical and tabular formats. The results and graphs can be printed. The data in excel format can be used for further analysis.

3 95 M.Mahendran et al, 2015 /Journal Of Applied Sciences Research 11(23), December, Pages:93-99 Fig. 3.1: Interface of EnginesoftLV Result and Discussion Experiments are performed on the diesel engine by varying fuel injection nozzle hole to arrive at optimum configuration. The results are discussed below. 4.1 Effect on Brake Thermal Efficiency (BTE): Effect of nozzle hole geometry for single hole nozzle and three hole nozzle on brake thermal efficiency is as shown in Fig respectively. It was found that, nozzle hole geometry has major influences on droplet size (spray) penetration. From Fig at corresponding Loads, it was noticed that, rise in brake thermal efficiency with increase in nozzle hole. This was due to increase in nozzle hole was responsible to rise in air fuel mixing,. Thus, in view of this BTE rises with number of hole. From the Fig below, it was observed that BTE 23.65% and 25.85% was higher at three hole nozzle, and 80% and full load respectively. The possible reason may be stated as, increase in BP leads to better atomization of fuel, improved spray characteristics and reduced physical delay period; which improved premixed combustion and rapid combustion rate. Owing to this, increase in brake thermal efficiency was observed. However too high BP will lead to delayed injection, negating gain due too high BP. Also, too high BP may responsible to higher velocity of droplet which will pass away without mixing air properly and lower brake thermal efficiency due to improper combustion. This results in reduction of the heat and time losses, resulting in a higher brake thermal efficiency, i.e. lower brake specific fuel consumption. Fig : Brake Thermal Efficiency (BTE) Vs Load

4 96 M.Mahendran et al, 2015 /Journal Of Applied Sciences Research 11(23), December, Pages:93-99 Fig : Brake Power (BP) Vs Load 4.2 Effect on Indicated Thermal Efficiency (ITE): Effect of nozzle hole geometry for single hole nozzle and three hole nozzle on Indicated thermal efficiency is as shown in Fig respectively. It was noticed that, rise in thermal efficiency with increase in nozzle hole. This was due to increase in nozzle hole was responsible to rise in air fuel mixing, fuel vaporization and improved combustion. Thus, in view of this ITE rises with number of hole. The possible reason may be stated as, increase in IP leads to better atomization of fuel, improved spray characteristics and reduced physical delay period; which improved premixed combustion and rapid combustion rate. Owing to this, increase in Indicated thermal efficiency was observed. However too high IP will lead to delayed injection, negating gain due too high IP. Also, too high IP may responsible to higher velocity of droplet which will pass away without mixing air properly and lower Indicated thermal efficiency due to improper combustion. It has also been observed that the smaller the orifice, the shorter the ignition delay. The smaller orifices also improve the mixing, which is shown by shorter combustion duration brake specific fuel consumption. Fig : Indicated Thermal Efficiency (ITE) Vs Load Fig : Indicated Power (IP) Vs Load

5 97 M.Mahendran et al, 2015 /Journal Of Applied Sciences Research 11(23), December, Pages: Effect on Specific Fuel consumption (SFC): Effect of nozzle hole geometry for single hole nozzle and three hole nozzle on specific fuel consumption is as shown in Fig respectively. The experiments were aimed to arrive at an optimum nozzle size that would give better fuel economy. It can be noticed from the Fig that the values of SFC are lower for three hole nozzle compared to single hole nozzle. This could be due to the fact that with increase in injection pressure, not only the fuel droplet size decreases but also increases the momentum of the droplets. It can be observed that SFC with three hole nozzle is the lowest, therefore from these set of experiments it is confirmed that the three hole nozzle yielding lower values. Also, it was observed that for the small size hole nozzle at any given Load yielded better performance. This is indicating the fact that smaller nozzle requires higher load condition to ensure complete combustion and to bring down fuel consumption. Fig : Specific Fuel Consumption (SFC) Vs Load 4.4 Effect on Nitrogen Oxides (NOx) emission: Effect of nozzle hole geometry and Load on NOx emission as shown in Fig respectively. NOx emission is result of oxidation of nitrogen at peak combustion temperature. At any nozzle hole operation with increase in Load, NOx emission was found to be increasing due to faster combustion and higher temperatures reached in the cycle as shown in the Fig This may be attributed to better atomization and improved mixing rate of fuel responsible to reduce delay period, and combustion duration, corollary it results in improved heat release rate, peak combustion and temperature. However, at Load at 80% or full load for single hole nozzle, the NOx emissions reduced for due to lower combustion phase and incomplete combustion caused by poor atomization, sprays characteristics and increased ignition delay at Load condition. Higher NOx emissions were observed with increased number of holes. The three hole nozzle injector provides better air and fuel mixing and hence higher premixed combustion occurs leading to higher NOx emissions. Fig : Nitrogen Oxides (NOx) Vs Load

6 98 M.Mahendran et al, 2015 /Journal Of Applied Sciences Research 11(23), December, Pages: Effect on Carbon Dioxide oxides (CO2) emission: Effect of nozzle hole geometry and Load on CO2 emission as shown in Fig respectively. As we know that CO2 emission is nothing but behaviour of complete combustion due to air-fuel mixture. Thus, due to increase in load from 80% to full load, CO2 emission for all tests was found to be increased. In addition, CO2 emission was found to be increased with increase in nozzle hole and Load. This adds advantage of increasing Load and nozzle hole up to certain limit. However at full load condition and three hole nozzle injector, CO2 emissions are high which is due to improved atomisation and proper combust Fig : Carbon Dioxide oxides (CO2) Vs Load 4.6 Effect on Carbon monoxide oxides (CO) emission: Effect of nozzle hole geometry and Load on CO emission as shown in Fig respectively. As we know that CO emission is nothing but behaviour of incomplete combustion due to rich air-fuel mixture. Thus, due to increase in load from 80% to full load, CO emission for all tests was found to be decreased. In addition, CO emission was found to be increased with increase in nozzle hole and Load. However at minimum Load condition and single hole nozzle injector, CO emissions are less which is due to improved atomisation and proper combustion. Fig : Carbon monoxide oxides (CO) Vs Load 4.7 Effect on Hydrocarbons (HC) emission: Effect of nozzle hole geometry and Load on HC emission as shown in Fig respectively. We know that, HC emission is caused due to low velocity of fuel which is not sufficient to penetrate air spray and induced improper air-fuel mixing or lower equivalence ratio (Ø). Also, more emission is found due to lack of fuel atomization or vaporization. As seen in Fig 4.7.1, for all nozzle hole operation HC emission was decreased with increase in Load condition. However at full load condition and three hole nozzle injector, HC emissions are less which is due to improved atomisation and proper combustion. Enhanced atomisation will also lead to a lower ignition delay.

7 99 M.Mahendran et al, 2015 /Journal Of Applied Sciences Research 11(23), December, Pages:93-99 Fig : Hydrocarbons (HC) Vs Load Conclusions: The Brake thermal efficiency for three hole nozzle at full load was found increase and brake specific fuel consumption found decrease. Though at 3 nozzle injector higher brake thermal efficiency and lower brake specific fuel consumption were obtained the percentage of improvement was maximum. So, increasing number of holes gave considerable effect on engine performance. At full load, CO and HC emissions were found same at single hole and three hole nozzle injector, NOX was found CO2 lowest at single hole nozzle injector. The economy of fuel is important for engine. At present scenario environmental protection is more important than fuel economy. So, decreasing emission is the primary concern which required moderate injection nozzle hole for a light duty diesel engine. References 1. Kennneth R Szukzyk, asporatation Whichfuel ethanolis bet butanol, International journal Issue Zhi-Hui Zhang, Rajasekhar Balasubram addition to diesel biodiesel blend on engine performance and Particulate emissions of a stationary diesel, 119: Mingfa Yao, Hu Wang, Zunqing Zh study of n-butanol additive and multi-injection on HD diesel engine performance and emissions, 220: Mughal, H.U., M.M.A. Bhutta, M. Athar, E.M. Shahid and M.S. Ehsan, The alternative fuels engines: performance analysis, IJST, Transactions of Mechanical Engineering, 36(M2): Bang-Quan He, Jie Yuan, Mao-Bin Liu, Hua Zhao, and emission characteristics of a n-butanol HCCI engine, Fuel, 115: Payri, R., F.J. Salvador, J. Gimeno, L.D. Zapata, Diesel nozzle geometry influence on spray liquid-phase fuel penetration in evaporative conditions, Fuel, 87: Martinez-Martinez, S., F.A. Sanchez-Cruz, J.M. Riesco-Avila, A. Gallegos-Munoz, S.M. Aceves, Liquid penetration length in direct diesel fuel injection, Appl. Therm. Eng., 28(14-15): Suh, H.K., C.S. Lee, Effect of cavitation in nozzle orifice on the diesel fuel atomization characteristics, Int. J. Heat Fluid Flow, 29(4): Payri, R., S. Molina, F.J. Salvador, J. Gimeno, A study of the relation between nozzle geometry, internal flow and sprays characteristics in diesel fuel injection systems, KSME Int. J. 18(7): Kent, J.C., G.M. Brown, Nozzle exit flow characteristics for square-edged and rounded inlet geometries, Combust. Sci. Technol., 30: Seang-wock Lee, Daisuke Tanaka, Jin Kusaka, Yasuhira Daisho, Effects of diesel fuel characteristics on spray and combustion in a diesel engine. JSAE Review., 23: Wategave, S.P., M.S. Sawant, M.S. Tandale, G. Suresh, V.S. Yaliwal, N.R. Banapurmath & P.G. Tewari, Effect of injection timing, injector opening pressure and nozzle geometry on the performance of a compression ignition engine operated on non-edible oil methyl esters from different sources, International Journal of Sustainable Engineering, DOI: / Ganesan, V., Engine emission and their control,(mcgrawhill,nd, 3rd Internaled.,2008,page ) 14. Rosli, Abu Bakar, Semin and Abdul Rahim Ismail, Fuel Injection Pressure Effect on Performance of Direct Injection Diesel Engines Based on Experiment. American Journal of Applied Sciences, 5(3): Celikten, Ismet, An experimental investigation of the effect of the injection pressure on engine performance and exhaust emission in indirect injection diesel engines, Applied Thermal Engineering, 23: